Energy companies led U.S. stock indexes to modest gains in early trading Monday as the price of crude oil headed higher. Utilities stocks were the only laggard. Investors had their eye on several big corporate deals.

HIGH ENERGY: Several oil industry stocks got a boost from rising crude prices. Hess was the biggest gainer in the S&P 500, climbing $1.69, or 3.5 percent, to $49.74. Rig operator Transocean rose 36 cents, or 2.9 percent, to $12.79.

CALL ANSWERED: Straight Path Communications more than doubled after the wireless spectrum license company agreed to be acquired by AT&T in a deal valued at $1.25 billion. Straight Path's shares gained $53.51, or 146 percent, to $89.99. AT&T slipped 3 cents to $40.56.

MERGING LANES: Shares in trucking companies Swift Transportation and Knight Transportation rose sharply on news the companies have agreed to combine in an all-stock deal. Swift shareholders will own a majority of the company, which will be called Knight-Swift Transportation Holdings. Swift's shares added $4.60, or 23 percent, to $24.62, while Knight gained $4.05, or 13.2 percent, to $34.70.

OIL: Benchmark crude oil was up 65 cents, or 1.2 percent, at $52.89 a barrel in New York. It added 54 cents to $52.24 a barrel late Friday. Brent crude, the standard for international oil prices, was up 52 cents, or 0.9 percent, at $55.76 a barrel in London.

CURRENCIES: The dollar rose to 111.30 yen from 111.15 yen late Friday. The euro strengthened to $1.0593 from $1.0588.